Characene

Characene was a Seleucid successor state in Mesopotamia which existed from 141 BC to 222 AD, with Charax Spasinu serving as its capital. It became an independent state after the Parthian invasion of Mesopotamia, occasionally joining the Roman Republic in its wars against the Parthians. In 222, the Persian Ardashir I established the Sassanid Empire, which conquered Characene that same year.